protocol
- Using protocol with a custom partition or session
- 方法
  - protocol.registerSchemesAsPrivileged(customSchemes)
  - protocol.registerFileProtocol(scheme, handler[, completion])
  - protocol.registerBufferProtocol(scheme, handler[, completion])
  - protocol.registerStringProtocol(scheme, handler[, completion])
  - protocol.registerHttpProtocol(scheme, handler[, completion])
  - protocol.registerStreamProtocol(scheme, handler[, completion])
  - protocol.unregisterProtocol(scheme[, completion])
  - protocol.isProtocolHandled(scheme, callback)
  - protocol.isProtocolHandled(scheme)
  - protocol.interceptFileProtocol(scheme, handler[, completion])
  - protocol.interceptStringProtocol(scheme, handler[, completion])
  - protocol.interceptBufferProtocol(scheme, handler[, completion])
  - protocol.interceptHttpProtocol(scheme, handler[, completion])
  - protocol.interceptStreamProtocol(scheme, handler[, completion])
  - protocol.uninterceptProtocol(scheme[, completion])

protocol

注册自定义协议并拦截基于现有协议的请求。

线程：主线程

实现与 file:// 协议具有相同效果的协议的示例:

const { app, protocol } = require('electron')
const path = require('path')
app.on('ready', () => {
  protocol.registerFileProtocol('atom', (request, callback) => {
    const url = request.url.substr(7)
    callback({ path: path.normalize(`${__dirname}/${url}`) })
  }, (error) => {
    if (error) console.error('Failed to register protocol')
  })
})

注意: 除了指定的方法, 其他方法只能在 app 模块的 ready 事件被触发后使用。

Using protocol with a custom partition or session

A protocol is registered to a specific Electron session object. If you don't specify a session, then your protocol will be applied to the default session that Electron uses. However, if you define a partition or session on your browserWindow's webPreferences, then that window will use a different session and your custom protocol will not work if you just use electron.protocol.XXX.

To have your custom protocol work in combination with a custom session, you need to register it to that session explicitly.

const { session, app, protocol } = require('electron')
const path = require('path')
app.on('ready', () => {
  const partition = 'persist:example'
  const ses = session.fromPartition(partition)
  ses.protocol.registerFileProtocol('atom', (request, callback) => {
    const url = request.url.substr(7)
    callback({ path: path.normalize(`${__dirname}/${url}`) })
  }, (error) => {
    if (error) console.error('Failed to register protocol')
  })
  mainWindow = new BrowserWindow({
    width: 800,
    height: 600,
    webPreferences: {
      partition: partition
    }
  })
})

方法

protocol 模块具有以下方法：

protocol.registerSchemesAsPrivileged(customSchemes)

customSchemes CustomScheme[]Note: This method can only be used before the ready event of the app module gets emitted and can be called only once.

Registers the scheme as standard, secure, bypasses content security policy for resources, allows registering ServiceWorker and supports fetch API.

Specify a privilege with the value of true to enable the capability. An example of registering a privileged scheme, with bypassing Content Security Policy:

const { protocol } = require('electron')
protocol.registerSchemesAsPrivileged([
  { scheme: 'foo', privileges: { bypassCSP: true } }
])

标准scheme遵循 RFC 3986 所设定的 URI泛型语法。例如, http 和 https 是标准协议, 而 file 不是。

将一个scheme注册为标准scheme, 将保证相对和绝对资源在使用时能够得到正确的解析。否则, 该协议将表现为 file 协议, 而且，这种文件协议将不能解析相对路径。

例如, 当您使用自定义协议加载以下内容时，如果你不将其注册为标准scheme, 图片将不会被加载, 因为非标准scheme无法识别相对路径:

<body>
  <img src='test.png'>
</body>

注册一个scheme作为标准scheme将允许其通过FileSystem 接口访问文件。否则, 渲染器将会因为该scheme，而抛出一个安全性错误。

默认情况下web storage apis (localStorage, sessionStorage, webSQL, indexedDB, cookies) 被禁止访问非标准schemes。 So in general if you want to register a custom protocol to replace the http protocol, you have to register it as a standard scheme.

protocol.registerSchemesAsPrivileged can be used to replicate the functionality of the previous protocol.registerStandardSchemes, webFrame.registerURLSchemeAs* and protocol.registerServiceWorkerSchemes functions that existed prior to Electron 5.0.0, for example:

before (<= v4.x)

// Main
protocol.registerStandardSchemes(['scheme1', 'scheme2'], { secure: true })
// Renderer
webFrame.registerURLSchemeAsPrivileged('scheme1', { secure: true })
webFrame.registerURLSchemeAsPrivileged('scheme2', { secure: true })

after (>= v5.x)

protocol.registerSchemesAsPrivileged([
  { scheme: 'scheme1', privileges: { standard: true, secure: true } },
  { scheme: 'scheme2', privileges: { standard: true, secure: true } }
])

protocol.registerFileProtocol(scheme, handler[, completion])

scheme String
handler Function - 回调函数
- request Object
  - url String
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function
  - filePath String (可选)
completion Function (可选)
- error Error注册一个 scheme 协议, 将该文件作为响应发送当要使用 scheme 创建 request 时, 将使用 handler(request, callback) 来调用 handler 。 completion 将在 scheme 注册成功时通过completion(null) 调用，失败时通过completion(error) 调用。

要处理 request, 应当使用文件的路径或具有 path 属性的对象来调用 callback。例如:callback(filePath)或 callback({ path: filePath }). The object may also have a headers property which gives a map of headers to values for the response headers, e.g. callback({ path: filePath, headers: {"Content-Security-Policy": "default-src 'none'"]}).

当 callback 被调用后，并且没有带着数字或 error 属性的对象时, request将会失败, 并且带有你指定的 error错误号。更多的错误号信息，您可以查阅网络错误列表.

By default the scheme is treated like http:, which is parsed differently than protocols that follow the "generic URI syntax" like file:.

protocol.registerBufferProtocol(scheme, handler[, completion])

scheme String
handler Function - 回调函数
- request Object
  - url String
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function - 回调函数
  - buffer (Buffer | MimeTypedBuffer) (可选)
completion Function (可选)
- error Error注册一个 scheme 协议, 将 Buffer作为响应发送

该用法与 registerFileProtocol 相同, 只是callback 会被Buffer对象或者带有data，mimeType和 charset属性的对象调用。

示例:

const { protocol } = require('electron')
protocol.registerBufferProtocol('atom', (request, callback) => {
  callback({ mimeType: 'text/html', data: Buffer.from('<h5>Response</h5>') })
}, (error) => {
  if (error) console.error('Failed to register protocol')
})

protocol.registerStringProtocol(scheme, handler[, completion])

scheme String
handler Function - 回调函数
- request Object
  - url String
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function - 回调函数
  - data String (可选)
completion Function (可选)
- error Error注册一个 scheme 协议, 将 String 作为响应发送

该用法与 registerFileProtocol 相同, 只是callback 会被String对象或者带有data，mimeType和 charset属性的对象调用。

protocol.registerHttpProtocol(scheme, handler[, completion])

scheme String
handler Function - 回调函数
- request Object
  - url String
  - headers Object
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function - 回调函数
  - redirectRequest Object
    - url String
    - method String
    - session Object (可选)
    - uploadData Object (可选)
      - contentType String - 内容的MIME类型。
      - data String - 要发送的内容。
completion Function (可选)
- error Error注册一个 scheme 协议, 将 HTTP 请求作为响应发送

该用法与 registerFileProtocol 相同, 只是callback 会被redirectRequest对象或者带有url, method, referrer, uploadData 和 session 属性的对象调用。

默认情况下, HTTP 请求会重复使用当前的 session。如果希望请求具有不同的session, 则应将 session设置为 null.

对于 POST 请求, 必须提供 uploadData 对象。

protocol.registerStreamProtocol(scheme, handler[, completion])

scheme String
handler Function - 回调函数
- request Object
  - url String
  - headers Object
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function - 回调函数
  - stream(ReadableStream | StreamProtocolResponse ) (可选)
completion Function (可选)
- error Error注册一个 scheme 协议, 将 Readable作为响应发送

该用法类似于 register{Any}Protocol ，只是callback 会被Readable对象或者带有data, statusCode 和 headers 属性的对象调用。

示例:

const { protocol } = require('electron')
const { PassThrough } = require('stream')
function createStream (text) {
  const rv = new PassThrough() // PassThrough is also a Readable stream
  rv.push(text)
  rv.push(null)
  return rv
}
protocol.registerStreamProtocol('atom', (request, callback) => {
  callback({
    statusCode: 200,
    headers: {
      'content-type': 'text/html'
    },
    data: createStream('<h5>Response</h5>')
  })
}, (error) => {
  if (error) console.error('Failed to register protocol')
})

可以传递任何可读取流 API 的对象(data/end/error 事件)。以下是如何返回文件的方法示例:

const { protocol } = require('electron')
const fs = require('fs')
protocol.registerStreamProtocol('atom', (request, callback) => {
  callback(fs.createReadStream('index.html'))
}, (error) => {
  if (error) console.error('Failed to register protocol')
})

protocol.unregisterProtocol(scheme[, completion])

scheme String
completion Function (可选)
- error Error取消对自定义scheme的注册

protocol.isProtocolHandled(scheme, callback)

scheme String
callback Function
- handled Booleancallback 会被调用，带有布尔值，表示是否已经有scheme 的处理程序。

即将弃用

protocol.isProtocolHandled(scheme)

scheme StringReturns Promise<Boolean> - fulfilled with a boolean that indicates whether there is already a handler for scheme.

protocol.interceptFileProtocol(scheme, handler[, completion])

scheme String
handler Function - 回调函数
- request Object
  - url String
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function - 回调函数
  - filePath String
completion Function (可选)
- error Error终止 scheme 协议, 并将 handler 作为该protocol新的处理方式，即返回一个file。

protocol.interceptStringProtocol(scheme, handler[, completion])

scheme String
handler Function - 回调函数
- request Object
  - url String
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function - 回调函数
  - data String (可选)
completion Function (可选)
- error Error终止 scheme 协议, 并将 handler 作为该protocol新的处理方式，即返回一个String。

protocol.interceptBufferProtocol(scheme, handler[, completion])

scheme String
handler Function - 回调函数
- request Object
  - url String
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function - 回调函数
  - buffer Buffer (可选)
completion Function (可选)
- error Error终止 scheme 协议, 并将 handler 作为该protocol新的处理方式，即返回一个Buffer。

protocol.interceptHttpProtocol(scheme, handler[, completion])

scheme String
handler Function
- request Object
  - url String
  - headers Object
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function
  - redirectRequest Object
    - url String
    - method String
    - session Object (可选)
    - uploadData Object (可选)
      - contentType String - 内容的MIME类型。
      - data String - 发送内容。
completion Function (可选)
- error Error终止 scheme 协议, 并将 handler 作为该protocol新的处理方式，即返回一个新 HTTP 请求。

protocol.interceptStreamProtocol(scheme, handler[, completion])

scheme String
handler Function
- request Object
  - url String
  - headers Object
  - referrer String
  - method String
  - uploadData UploadData[]
- callback Function
  - stream(ReadableStream | StreamProtocolResponse ) (可选)
completion Function (可选)
- error Error它与 registerStreamProtocol方法相同, 不过它是用来替换现有的protocol处理方式。

protocol.uninterceptProtocol(scheme[, completion])

scheme String
completion Function (可选)
- error Error移除为 scheme 安装的拦截器，并还原其原始处理方式。